Involuntary movement disorders of the human body cause impairment of proper motor function and result in a substantial decrease in quality of life, as well as various health problems. One such pathology, Essential Tremor (ET), is a neurodegenerative disease that causes an involuntary, tremulous movement which can affect almost any part of the body. Most often ET is presented in extremities of the body, such as the arms and hands, but ET can also be found in the head, voice, leg, and tongue, for example. ET is a kinetic tremor, often appearing during a movement of a body part, and is also a postural tremor, occurring when a subject maintains a position against gravity.
The cause of ET is currently unknown, rendering treatment of the disease more difficult. One treatment method is drug therapy, and the most common drugs used in such therapy are propanolol and pirimidone. Propanolol is a beta blocker that is used to treat hypertension and has numerous secondary effects that may include dizziness, difficulty sleeping, and nausea, among others. Pirimidone is an anticonvulsive that acts to decrease abnormal electrical activity on the brain and also has numerous secondary effects that may include somnolence and nausea, among others. Neither drug has shown to be efficient in reducing tremor amplitude.
Other treatment methods include brain operations such as thalamotomy and deep brain stimulation. Thalamotomy is the precise destruction of the thalamus, which controls involuntary movements. This type of surgery is expensive and is associated with a high risk of undesirable side effects. Deep brain stimulation is the implantation of electrodes in an area of the brain that controls involuntary movements, which are connected via cables to the chest of a patient.